This former tuberculosis research hospital endeavored to cure the dreaded disease with fresh air and positive attitudes.

The world's longest known cave system.

This award-winning men's bathroom was just too beautiful to not allow women to see.

This church houses the “incorrupt” body of its founding Bishop.

This replica of the Greek structure is in the heart of Nashville.

It may take some time to locate, but it's sure to warm even a heart of stone.

After the attack on Pearl Harbor, rocks and fossils from every U.S. state were collected into a pyramid of national unity.

Disney's abandoned animal island is now an overgrown ruin that was almost the coolest attraction ever.

Disney World's very first waterpark is now an abandoned ruin being reclaimed by the swamp.

Once featuring over 60 miniature replicas of famous Chinese locations, the Splendid China theme park was completely abandoned and is now mostly rubble.

The only runway directly into the magic kingdom has been closed since 1972, but it still sings to you if you drive fast enough.

This fairytale-inspired cottage was created by a university literature professor.

Island ghost town detailing Flagler's folly in building the Overseas Railroad.

Ancient human, animal, and geometric figures drawn in the earth.

Limestone caves with spectacular showcase chambers.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

This golf ball–shaped former desert real estate office now houses a UFO museum.

After a short-lived attempt to bring America in line with the rest of the world, this road was left in metric.

This immigrant bridge once spanned the Thames but is now a fixture of an Arizona city.

The biggest solar telescope in the world helps reveal the secrets of our sun.

In Tucson a giant metal snake helps pedestrians cross a busy highway.

A cabinet of curious mathematical models and old calculators.

Giant telescope mirrors built in a spinning furnace under a college football stadium.

Religious statues built because of one man's bargain with God fill this peaceful sculpture garden.